#define _CRT_SECURE_NO_WARNINGS 1
#include<stdio.h>
int cot(int n)
{
	int sum = 1;
	for (int i = 1; i <=n; i++)
	{
		sum *= i;
	}
	return sum;
}
int main() {
	int n = 0;
	scanf("%d", &n);
	int num = cot(n);
	printf("%d", num);
	return 0;
}